The aforementioned application discloses a grate comprising a one-piece frame-like base plate supporting a plurality of replaceable rod-like wear elements. At its forward area the plate is provided with integral, transversely extending, longitudinally spaced recesses and projections or guides. The wear elements are formed with integral complementary guides interfitting with those of the plate so that each may, in turn, be slid into emplaced position from one side edge of the plate. In such positions each element is held against upward and downward displacement with respect to the plate. When all elements are emplaced in side-by-side contact they fill the extent of the guide means. The two elements at the respective ends of the row thus formed are held against lateral displacement by contact with side walls of the stoker or plate support. Thus, all wear elements are integrally associated with the grate plate and their upper surfaces conjointly form a smooth materials-supporting surface.
The aforesaid construction has certain disadvantages because of difficulty in the replacement of individual wear elements. Further, since the end elements are in contact with side walls of the support, they are subject to wear in the case of reciprocating plates and may become loose and displaced. This may result in increased rate of wear of all the elements; and when excessive wear occurs the spaces formed by and between contiguous elements may be increased to an undesirable extent and thus permit an undesirable increase in riddlings and detritus.